1. Field of the Invention
The present invention relates to a continuous conveying type bag-filling packaging machine and more particularly to an empty bag supplying apparatus and a product-filled bag extraction apparatus that are used in the continuous conveying type bag-filling packaging machine.
2. Prior Art
In a continuous conveying type bag-filling packaging machine, empty bags are supplied to gripper pairs that move continuously along a loop-form endless path, both side edges of bags are gripped by the gripping sections of gripper pairs so that the bags are suspended, and various packaging treatments such as opening of the bag mouths, filling of the bags with contents and sealing of the bag mouths, etc. are performed on these bags.
In such a continuous conveying type bag-filling packaging machine, an empty bag supplying apparatus and a product-filled bag extraction apparatus are employed. The empty bag supplying apparatus supplies empty bags to gripper pairs, and the product-filled bag extraction apparatus receives product-filled bags and then discharges the product-filled bags to the outside of the movement path.
The empty bag supplying apparatus used in the continuous conveying type bag-filling packaging machine must cause the bags to move in conformity with the gripper pairs of the bag-filling packaging machine, and it also must transfer the empty bags to the gripper pairs during this movement.
Various proposals have been made concerning such empty bag supplying apparatuses. However, conventional empty bag supplying apparatuses of this type involve respective problems:
(1) Endless belt type empty bag supplying apparatus (Japanese Patent Application Laid-Open (Kokai) No. 59-221201)
In this apparatus, a ventilated endless belt that is mounted between two drums is used. The empty bags are caused to adhere to the surface of the belt by vacuum suction and supported by supporting claws, and then, the empty bags are caused to move in conformity with the gripper pairs. Since this apparatus is large, a large installation space is required for the packaging machine as a whole. Furthermore, since the structure of the apparatus is complicated, the apparatus is expensive and has poor cleaning and maintenance characteristics.
(2) Rotary type empty bag supplying apparatus (Japanese Patent Application Laid-Open (Kokai) No. 6-199317, Japanese Patent Application Laid-Open (Kokai) No. 8-301232)
In these prior arts, empty bags are suction-chucked by suction disks attached to the circumference of a rotating member at equal intervals, so that the empty bags are caused to move in conformity with the gripper pairs. However, the structures of these prior art apparatuses are extremely complicated, and they are expensive and have poor cleaning and maintenance characteristics.
(3) Reciprocating pivoting type empty bag supplying apparatus (Japanese Utility Model Application Publication (Kokoku) No. 3-12645)
In this bag supplying apparatus, the upper edges of empty bags are held by opening and closing holding plates that are disposed on the circumference of a tracking table. This tracking table makes a back and forth rotating motion. The holding plates are caused to move in conformity with the gripper pairs and returned to their original positions after the transfer of the empty bags. In this apparatus, the tracking mechanism is complicated. Thus, the apparatus is expensive and has poor cleaning and maintenance characteristics.
Meanwhile, as to the product-filled bag extraction apparatus, when the product-filled bags are removed from a continuous conveying type bag-filling packaging machine, the gripping sections of the gripper pairs are opened so that the product-filled bags are dropped onto a conveying means such as a conveyor belt, etc., either directly or via a chute, etc., and then the product-filled bags are conveyed out to an after-process. In such an apparatus, however, it is difficult to drop the product-filled bags into fixed positions on the conveying means in a secure and stable manner.
The present invention was made in light of the above-described problems relating to such empty bag supplying apparatuses and product-filled bag extraction apparatus used in continuous conveying type bag-filling packaging machines.
It is an object of the present invention to provide an empty bag supplying apparatus and a product-filled bag extraction apparatus which are simple in structure, thus reducing the costs and providing superior advantages in terms of cleaning and maintenance characteristics.
The above object is accomplished by a unique structure for an empty bag supplying apparatus used in a continuous conveying type bag-filling packaging machine.
More specifically, the empty bag supplying apparatus receives empty bags that are positioned in a vertical attitude with mouths of the bags facing upward and transfers the bags to respective gripper pairs of the bag-filling packaging machine, the gripper pairs being moved continuously at a constant speed and at a uniform spacing and gripping both side edges of the bags by means of its gripping sections and conveying the bags in a vertically suspended fashion, wherein
the empty bag supplying apparatus is comprised of:
downward-facing bag holding members which open and close at a specified timing so as to hold upper portions of the bags when closed,
a reciprocating movement mechanism which causes the bag holding members to perform a reciprocating motion along an arc-shaped path on a horizontal plane and which causes the bags held by the bag holding members to be set substantially parallel to a direction of movement of the gripper pairs at all times, and
a bag transfer region that is established at an intermediate point on the arc-shaped path, the arc-shaped path substantially overlapping a movement path of the gripping sections of the gripper pairs within the bag transfer region, and a speed of the reciprocating motion of the bag holding members in a direction of movement of the gripper pairs being set to be substantially equal to a moving speed of the gripper pairs at least within the bag transfer region.
In the above structure, the xe2x80x9cbag transfer regionxe2x80x9d refers to a region in which both side edges of the empty bags held by the bag holding members are gripped by the gripper pairs, and the bag holding members are opened so that the empty bags are released, so that the empty bags are transferred from the bag holding members to the gripper pairs.
In the present invention, when the bag holding members are moved in the direction of movement of the gripper pairs, this is referred to as an advancing motion; and when the bag holding members are moved in the opposite direction, this is referred to as a returning motion.
The above object is further accomplished by a unique structure for a product-filled bag extraction apparatus used in a continuous conveying type bag-filling packaging machine.
More specifically, the product-filled bag extraction apparatus receives product-filled bags, upon which packaging treatment has been completed, from respective gripper pairs of the bag-filling packaging machine and then discharges the product-filled bags to an outside of the movement path of the gripper pairs, the gripper pairs being moved continuously at a constant speed and at a uniform spacing and gripping both side edges of the bags by means of its gripping sections and conveying the bags in a vertically suspended fashion wherein:
the product-filled bag extraction apparatus is comprised of:
downward-facing bag holding members which open and close at a specified timing so as to hold upper portions of the bags when closed,
a reciprocating movement mechanism which causes the bag holding members to perform a reciprocating motion along an arc-shaped path on a horizontal plane and which causes the bags held by the bag holding members to be set substantially parallel to a direction of movement of the gripper pairs at all times, and
a bag receiving region that is established at an intermediate point on the arc-shaped path, the arc-shaped path substantially overlapping a movement path of the gripping sections of the gripper pairs within the bag receiving region, and a speed of the reciprocating motion of the bag holding members in a direction of movement of the gripper pairs being set to be substantially equal to a moving speed of the gripper pairs at least within the bag receiving region.
In the above structure, the xe2x80x9cbag receiving regionxe2x80x9d refers to a region in which the upper portions of the product-filled bags whose side edges are gripped by the gripper pairs are held by the bag holding members, and the gripper pairs are opened so that the product-filled bags are released, thus causing the product-filled bags to be received by the bag holding members from the gripper pairs.
Preferably, in the above empty bag supplying apparatus and in the above product-filled bag extraction apparatus, a plurality of the bag holding members are attached to a common supporting member that performs a reciprocating motion along an arc-shaped path and also performs a translational motion during this reciprocating motion. Furthermore, the bag holding members are preferably disposed along the direction of movement at the same spacing as the gripper pairs.
Furthermore, the mechanism that causes the supporting member to perform the reciprocating motion comprises: two pivoting shafts disposed with a specified distance in between, and respective swing shafts which are always positioned at equal distances and in the same direction with respect to the respective pivoting shafts, the swing shafts swinging about the respective pivoting shafts as the pivoting shafts rotate; and the supporting member performs the translational motion as a result of being connected to the swing shafts.
The supporting member that performs a translational motion always faces in the same direction. As a result, the bag holding members also always face in the same direction (with the holding surfaces parallel to the direction of movement of the gripper pairs) during the reciprocating motion.
The empty bag supplying apparatus and the product-filled bag extraction apparatus of the present invention are used mainly in cases where the endless path of the continuously moving gripper pairs is set on a horizontal plane. However, they can be used in cases where the endless path is set vertically.
Furthermore, the empty bag supplying apparatus and the product-filled bag extraction apparatus are used mainly for rectilinear regions of the endless path of the gripper pairs. However, if the curvature is relatively small, in other words, when the gripper pairs are installed on the circumference of a relatively large-diameter rotating table and rotate continuously, then the empty bag supplying apparatus and the product-filled bag extraction apparatus can be used in regions in which the gripper pairs are moved along a curved endless path. In this case, the arc-shaped path of the bag holding members can be set with the tangential direction of the endless path of the gripper pairs in the bag transfer region and in the bag receiving region of the arc-shaped path viewed as the direction of movement of the gripper pairs.